Intraoperative echocardiography can be used easily and safely during open heart surgical operations. Combining this technique with the use of myocardial echo contrast agents could allow the development of a method to assess regional myocardial perfusion and myocardial function intraoperatively before and after revascularization procedures. This proposal deals with the investigations which are required to characterize the capabilities of this method and to transfer it to clinically effective use for humans. Specific areas requiring investigation include: l) determining the accuracy of this technique in evaluating regional differences in coronary flow during open heart operations, 2) confirming the effectiveness of the echo contrast agents themselves during delivery of cold cardioplegia, and 3) characterizing the intraoperative usefulness of this method as a real time intervention capable of improving the quality of coronary artery revascularization. Specific modification of existing algorithms relating contrast effect to flow and function during open heart surgery appear necessary.